• Korean Journal of Environment and Ecology
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• v.33 no.5
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• pp.596-604
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• 2019

This study conducted a sediment culture experiment to investigate the effects of sediment oxygen demand (SOD) and environmental factors on sediment and water quality. We installed a leaching tank in the laboratory, cultured it for 20 days, and analyzed the relationship between P and Fe in the sediment. As a result, the dissolved oxygen of the water layer decreased with time, while the oxidation-reduction potential of the sediment progressed in the negative direction to form an anaerobic reducing environment. The SOD was measured to be 0.05 mg/g at the initial stage of cultivation and increased to 0.09 mg/g on the 20th day, indicating the tendency of increasing consumption of oxygen by the sediment. The change is likely to have caused by oxygen consumption from biological-SOD, which is the decomposition of organic matter accumulated on the sediment surface due to the increase of chl-a, and chemical-SOD consumed when the metal-reducing product produced by the reduction reaction is reoxidized. The correlation between SOD and causality for sediment-extracted sediments was positive for Ex-P and Org-P and negative for Fe-P. The analysis of the microbial community in the sediment on the 20th day showed that anaerobic iron-reducing bacteria (FeRB) were the dominant species. Therefore, when the phosphate bonded to the iron oxide is separated by the reduction reaction, the phosphate is eluted into the water to increase the primary productivity. The reduced substance is reoxidized and contributes to the oxygen consumption of the sediment. The results of this study would be useful as the reference information to improve oxygen resin.

• Journal of the Korean Society for Railway
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• v.11 no.5
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• pp.455-464
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• 2008

This paper examines the situation and tasks of competitive systems of EU transport market focusing on railways. Recently, the EU transport market has changed radically, thanks to an increasingly competitive rail market. The European Commission has stimulated the creation of a competitive environment that will enhance the position of rail. Some scholars have insisted that the rail market is more monopolistic than competitive. However, the case of UK rail privatization suggests this is not the case. Moreover, some countries have a rail market that is more competitive. We draw on a wide range of sources including statistics and analyses of recent phenomena. These demonstrate the emergence of competitive markets in EU rail and the difficulty of developing a competitive market. With regard to the adoption of the competitive market, we examine three things. First, we observe recent cases and trends in competitive markets. Second, we compare the result of competitive markets and non-competitive markets within EU nations. Third, we demonstrate factors of formation of competitive markets and the possible expansion. We identified differences within open market policies amongst EU nations. Although a competitive EU rail market may have some difficulties, it will steadily begin to overcome technological differences and a lack of funds, because EU countries have a common goal, which is to develop the railways, solving, wherever possible both environmental and energy problems. Through this analysis, we found that the free market in EU rail will be extended to deliver efficiency and quality service.

• Journal of the Korea Society of Computer and Information
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• v.25 no.6
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• pp.109-117
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• 2020

An edutainment system aims to help learners to recognize problems effectively, grasp and classify important information needed to solve the problems and convey the contents of what they have learned. Edutainment contents can be usefully applied to education and training in the both scientific and industrial areas. Our present work proposes an edutainment system that can be applied to a drug discovery process including virtual screening by using intuitive multi-modal interfaces. In this system, a stereoscopic monitor is used to make three-dimensional (3D) macro-molecular images, with supporting multi-modal interfaces to manipulate 3D models of molecular structures effectively. In this paper, our system can easily solve a docking simulation function, which is one of important virtual drug screening methods, by applying gaming factors. The level-up concept is implemented to realize a bio-game approach, in which the gaming factor depends on number of objects and users. The quality of the proposed system is evaluated with performance comparison in terms of a finishing time of a drug docking process to screen new inhibitors against target proteins of human immunodeficiency virus (HIV) in an e-drug discovery process.

• Korea journal of population studies
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• v.11 no.1
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• pp.14-31
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• 1988

The national family planning program in Korea, which was instituted as an integral part of the nation's economic development plans since 1962, has contributed greatly to a reduction in the fertility and population growth rate. The total fertility rate dipped from 6.0 births per women in 1960 to 2.0 in 1985, and the population growth rate rom 2.84 percent per year to 1.25 percent during the same period, while the contraceptive practice rate for the 15-44 married women increased from 9 percent in 1965 to 70 percent in 1985. Study findings indicate that the fertility reduction in the past 26 years is largely attributed to the virgorous implementation of the national family planning program, rising age at marriage, wide-spread use of induced abortion, and the changes in attitude regarding the value of children that came into being in the wake of the rapid socio-economic development over the period. Among the strengths of the national family planning program are the following : 1) a pluralistic system of program manageent with active participation of various government and voluntary organizations, 2) utilization of a large corps of family planning field workers to conduct face-to-face communication and motivation activities, 3) use of private physicians with government support to provide contraceptive services, 4) a systematic program management system including program planning of traget allocation, evaluation, and supervision with a broad MIS and award system, 5) numerous incentive and disincentive schemes for stimulating the small family norm and contraceptive use, and 6) strong commitments to the family planning program by political leaders. The new demographic targets during the Sixth Five-Year Economic and Social Development plan period(1987-91) have been set for a further reduction in the population growth rate to 1.0 percent by 1993, assuming that the TFR will decline to 1.75 level in 1995. This target is, however, not easy to achieve due to anticipated unfavorable factors like the strong boy preference, high discontinuation rates of reversible contraceptive methods, fertility termination-oriented contraceptive use, a plateau level of contraceptive practice rate that has mostly accounted for a sterilization, shortened length of birth intervals, and the changing patterns of contraceptive mix. The recent changes in contraceptive and fertility behaviors clearly indicate that the past quantity-oriented management system of the national program should be redirected toward a quality-oriented approach. Particularly, program efforts should be expanded to recruit new contraceptive users in the 20s of younger age groups, both for birth spacing and controlling their fertility since the women aged 20 to 29 account for more than 80 percent of the total annual births in recent years. In addition, the current contraceptive fee system of the national family planning program should be gradually shifted from free contraceptive services to a acceptor's charge system, and the provision of contraceptive services through the medical insurance system, which will cover the entire population by 1989, should be accelerated as a means of integration of family planning program with other health programs.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.641-647
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• 2015

Monitoring of soil fertility by long-term application of fertilizers is necessary to improve the fertility of soil and the productivity of crop. The objective of this study was conducted to investigate the changes of exchangeable Mg by continuous application of fertilizers from 1969 to 2014. The treatments were no fertilization (No fert.) and fertilization (NPK, NPK+C, NPK+S, and NPK+CS). The concentration of exchangeable Mg in No fert., NPK+C, and NPK+S treatments tended to increase from 1965 to 1975, but decrease gradually from 1976 to 1987, and increase again after 1988. Based on these, the changes of exchangeable Mg were divided into period I ('69 ~'75), period II ('76~'87), and period III ('88~'14). Especially, exchangeable Mg decreased in the period II. This was presumed that a significant amount of Mg from topsoil were leached into subsoil by break of plow pan and some of subsoil was incorporated into topsoil according to change of plowing depth by replacement of tillage machinery. It could be possible that exchangeable Mg in NPK, NPK+S, and NPK+CS was accumulated in the depth of 15~20 cm. For the period III, exchangeable Mg in No fert., NPK, NPK+C, NPK+S, and NPK+CS treatments increased at rates of 0.013, 0.018, 0.015, 0.023, and $0.024cmolckg^{-1}{\cdot}yr^{-1}$ respectively. Exchangeable Mg level in NPK+S was lower than the other treatments in the period I and period II, but higher than in the period III. This result was attributed to replacement of silicate fertilizer type from wollastonite (Mg 0.3%) to silicate fertilizer (Mg 3%). Also, exchangeable Mg level of No fert. treatment increased, which showed that Mg concentration of irrigated water had the greatest impact on Mg accumulation of soil. Recently, Mg level of irrigated water tended to increase, indicating that Mg concentration of water will affect greatly the concentration of exchangeable Mg of soil in the future. Like these, the changes of exchangeable Mg were greatly influenced by agricultural environment such as plowing depth, plow pan, content of fertilizer, and quality of irrigated water. Considering these agricultural environment, the proper management of soil is needed for the improvement of soil fertility and crop productivity.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.498-501
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• 2011

The nitrogen, phosphorus, and potassium contents are the key factors to determine the quality of organic fertilizers and right amount of application for agricultural uses. The major nutrient contents in raw materials used for making organic fertilizers and products were evaluated in this study. Among the raw materials that were investigated, soybean cake gave the highest total N content at $76g\;kg^{-1}$, followed by perilla cake ($70g\;kg^{-1}$), rape seed oil cake ($66g\;kg^{-1}$), cotton seed cake ($54g\;kg^{-1}$), and rice bran ($22g\;kg^{-1}$). We investigated 43 organic fertilizers and our results showed widely varied concentrations of major nutrients : total N at $30.5-139g\;kg^{-1}$, total $P_2O_5$ at $2.3-96.3g\;kg^{-1}$, and total $K_2O$ at $0.1-29.3g\;kg^{-1}$. Our study would like to emphasize the importance of nutrient content labeling in packed organic fertilizers to be able to know its efficiency and for determining the right amount for application.

• Journal of radiological science and technology
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• v.44 no.5
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• pp.545-554
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• 2021

According to the changes of the medical environment of the times, it is necessary to discuss the issues of the doctor's medical guidance and to conduct continuous research so that alternatives can be prepared systematically. Furthermore, in order to enhance the professionalism of radiological technologists and to develop the medical technician system, the new Radiological Technologist Independent Act has been established, which contains the overall contents of the scope of work, professional qualifications, and specialized education of radiological technologists, and provides quality medical services to patients through professional procedures and treatment. In order to increase the level of medical care, the purpose, definition, mission, role, and scope of work specified in the Medical Act, Medical Service Technologists, etc. Act, the Enforcement Decree, and the Enforcement Rules were variously analyzed and new directions were presented. First, the definition of a medical technician should use a generic term so that the factors of conflict and prejudice could be resolved. Second, change the doctor's guide to doctor's prescription; and then legislate the authority to sign and write medical records after examination by radiological technologists, thereby prohibiting unlicensed technicians that seriously endanger patient safety. Third, an accurate definition of radiological technologists' roles should be established; not only selection and management of radiological technologists' work but also procedures and treatment for each radiology field should be specified to suit the current medical system. Fourth, a professional radiological technologists' qualification system and a specialized education system should be established in order to secure human resources that could provide patients trust in procedures and treatment based on professional knowledge and experience in the field of radiology. Fifth, the Education and Evaluation Institute should be operated in Korea education system to educate the professional knowledge and competency for students. In addition, it is necessary to in-depth analysis of foreign cases could be applied to the medical system and education system in Korea; it could strive to nurture systematic human resources.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.585-590
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• 2021

Wrist braces are being used for patients with wrist trauma. Recently, many studies have been conducted to manufacture custom wrist braces using 3D printing technology. Such 3D printing customized orthosis has the advantage of reflecting various factors such as reflecting different shapes for each individual and securing breathability. In this paper, the stress on the orthosis by the number and position of Velcro bands that should be considered when manufacturing a 3D printing custom wrist brace was analyzed. For customized orthosis, 3D modeling of the bone and skin regions was performed using an automatic design software (Reconeasy 3D, Seeann Solution) based on CT images. Based on the 3D skin area, a wrist orthosis design was applied to suit each treatment purpose. And, for the elasticity of the brace, a wrist brace was manufactured with an FDM-type 3D printer using TPU material. To evaluate the effectiveness according to the number and position of the Velcro band of the custom 3D printed wrist brace, the stress distribution of the brace was analyzed by the finite element method (FEM). Through the finite element analysis of the wrist orthosis performed in this study, the stress distribution of the orthosis was confirmed, and the number and position of the orthosis production and Velcro bands could be confirmed. These experimental results will help provide quality treatment to patients.

• Journal of Soil and Groundwater Environment
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• v.26 no.6
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• pp.130-143
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• 2021

Wetlands are one of the most representative groundwater dependent ecosystems(GDEs) that require access to groundwater on a permanent or intermittent basis to maintain their biological communities and ecological processes. In this study, the seasonal characteristics of the GDEs in Baekseok Reservoir Wetland were evaluated through the monitoring of the temporal and spatial community of benthic macroinvertebrates in the wetland. The appearance of benthic macroinvertebrates appearance was changed seasonally depending on environmental factors such temperature, precipitation and water level for their habitat and it also showed the clear spatial difference in the wetland. The scores of Diversity index(H'), Richness Index (R1) and the Ecological score of benthic macroinvertebrates (TESB/AESB) were relatively high at St.3 and 4(i.e., north area) where groundwater inflows into wetland(i.e., high ²²²Rn conc.). The statistical analysis (ANOVA test and PCA) investigated the correlation among the benthic macroinvertebrates' community, groundwater level, wetland water level and water quality. The results showed that the community of benthic macroinvertebrates at St. 3 and 4 in Baekseok Reservoir Wetlands was spatially dependent on groundwater level and groundwater inflow. The characterization and assessment of GDEs requires understanding the hydrological, biogeochemical and biological process and this study will provide information for characterization and assessment of GDEs.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.4
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• pp.413-418
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• 2020

It is necessary to manage the prediction accuracy of the machine learning model to prevent the decrease in the performance of the grid network condition prediction model due to overfitting of the initial training data and to continuously utilize the prediction model in the field by maintaining the prediction accuracy. In this paper, we propose an automation technique for maintaining the performance of the model, which increases the accuracy and reliability of the prediction model by considering the characteristics of the power grid state data that constantly changes due to various factors, and enables quality maintenance at a level applicable to the field. The proposed technique modeled a series of tasks for maintaining the performance of the power grid condition prediction model through the application of the workflow management technology in the form of a workflow, and then automated it to make the work more efficient. In addition, the reliability of the performance result is secured by evaluating the performance of the prediction model taking into account both the degree of change in the statistical characteristics of the data and the level of generalization of the prediction, which has not been attempted in the existing technology. Through this, the accuracy of the prediction model is maintained at a certain level, and further new development of predictive models with excellent performance is possible. As a result, the proposed technique not only solves the problem of performance degradation of the predictive model, but also improves the field utilization of the condition prediction model in a complex power grid system.